How Contagious is Giardia?
My eight-month-old Shih Tzu pup Ike who I adopted from a rescue was diagnosed with giardia and tapeworm. Could my four-year-old Shih Tzu Duffy catch giardia from him? He is on Panacur, and metronidazole for 10 days, and 2 Drontal tabs for worms.
The microscopic intestinal parasite is the subject of much debate among veterinarians. Some experts doubt that Giardia causes disease in dogs. Others feel that it is a dangerous pathogen that is potentially transmissible to humans. Just about the only thing everyone can agree upon is that Giardia is hard to eliminate from the intestines of dogs.
I feel that Colorado State University professor of veterinary medicine Dr. Michael Lappin put it best at a lecture several years ago. Giardia probably is a pathogen in dogs. But it is a weak pathogen.
Many dogs infested with Giardia show no symptoms (this is the origin of the debate over whether Giardia causes disease in dogs). When other conditions (such as worms, dietary indiscretion, or inflammatory bowel disease) cause the health of the intestinal tract to deteriorate, the Giardia "have a party" (to quote Dr. Lappin) and make the problem worse.
I therefore never panic over a diagnosis of Giardia. Duffy theoretically could catch Giardia from Ike. So could you (although again, the human health threat from canine Giardia is hotly debated). Practice good hygiene to reduce the risk of transmission. This boils down to picking up all of Ike's feces immediately, and thoroughly washing your hands afterwards.
A combination of Panacur (fenbendazole) and metronidazole is the currently preferred treatment for Giardia. I wouldn't treat Duffy unless he gets sick.
Finally, a warning about Giardia tests. As I already mentioned, Giardia frequently is found in the intestines of healthy dogs. Follow up testing of Ike is likely to show ongoing infestation. If Ike is not sick, have a serious heart-to-heart talk with your vet about this matter before you engage in round after round of treatment.